The efforts have been further continued to increase the preparative capability of the high-speed countercurrent chromatography (HSCCC) with a large diameter coil. The apparatus is a bench top model of the horizontal flow-through coil planet centrifuge which produces the suitable synchronous planetary motion of the column holder at 15 cm revolutional radius. The separation column was prepared from a piece of 5.5 mm i.d. FEP tubing which was coaxially coiled around the holder. The short column for preliminary separations was prepared from 4.2 m long, 112 ml capacity tubing and the long multilayer coil for preparative separations, from a 30 m long, 750 ml capacity tubing. The performance of the present scheme was assessed with a standard set of dinitrophenyl (DNP) amino acid samples and a two-phase solvent system composed of chloroform, acetic acid, and 0.1N hydrochloric acid at a volume ratio of 2:2:1. A series of experiments was performed to study the effects of revolutional speed (50 rpm - 400 rpm), flow rate (120 ml/h and 500 ml/h) and helical diameter of the column (7.5 cm, 11.25 cm, and 15 cm) on the retention of the stationary phase and peak resolution. Results showed that both the revolutional speed and the helical diameter plays a critical role in hydrodynamic distribution of the two solvent phases in the coil. With the proper mode of elution, a large amount of the stationary phase was retained in the coil resulting in excellent peak resolution even under a high flow rate of 500 ml/h. Large-scale preparative separations with 20 ml sample volume have been successfully demonstrated with the multilayer coil.